Euphemism for the vomit. "Urf" is useable as a noun or verb and is directly synonymous with "ralph". Urf is a much more useful word as it best approximates the wretched sound of a person who is delivering street pizza by inverting their tummy.

Man, Frank was so screwed up on bourbon last night he stepped outside to urf. In the morning the neighbors smelled something nasty and saw the urf in the bird bath.

The definition of the word urf is the undeniable truth that something terrible has happened. If something terrible has happened, you say urf and then everything is better. I think people who use the word urf are the coolest people in the world and if you disagree with me then I'll hurt you. So in theory the word irf is the best word in the world, and I just love it so so so much. XoXo bitches.

URF, my life sure does suck. Oh wait now it's super because I used the word urf.